The debate in California over the dangers and use of oil and gas drilling techniques like fracking and acidization have been framed the last few years by the potential bonanza they hold for tapping reputedly the nation's largest reservoir of oil—in the Monterey Shale.

On Tuesday, Louis Sahagun at the Los Angeles Times reported that that powerful argument by the oil industry, which has swayed politicians and public perception, was about to be dashed by the U.S. Energy Information Administration (EIA).

The agency will release a report, probably next month, that reduces the projected 13.7 billion barrels of recoverable oil in Central California by 96%, to just 600 million barrels. The EIA based its projection on the failure of limited fracking operations already in place in Central California shale country to effectively overcome the challenging geological formations.

Salivating politicians were regularly peppered with estimates that the oil boom would create up to 2.8 million new jobs in California and add $24.6 billion in annual state tax revenue.

Techniques like fracking and acid stimulation—the latter injects large amounts of hydrochloric or hydrofluoric acid into wells to dissolve rock formations—are used to reach deposits out of reach via conventional drilling. Fracking has been linked to groundwater contamination, air pollution, releases of methane gas, micro-earthquakes and sinkholes. It also uses a lot of water.

Fracking has been around for decades but wasn't used much and didn't get much scrutiny until new technology gave life to old and previously unsuitable fields. In fact, it was largely unregulated in California until Senate Bill 4 was passed last September.

That legislation has been criticized by environmentalists for its watered-down reporting requirements that pretty much allowed business as usual until an environmental report is put together—in July 2015. As it stands now, drillers can claim that some of the toxic chemicals they pump into the ground under high pressure don't need to be made public because they are trade secrets.

Virtually every story about fracking in California mentions the Monterey Shale, 17,847 acres that stretch across 79 parcels in three counties—Monterey, San Benito and Fresno. Shale oil drilling has been a boon to the industry in Texas and North Dakota, and those states don't have nearly as much of it as California.

Unfortunately, not all shale is created alike. The shale in those states is laid down in relatively even layers with oil laced between the layers. California shale has been folded, smashed and smushed by earthquakes, making it much more difficult to extract oil from it.

“From the information we've been able to gather, we've not seen evidence that oil extraction in this area is very productive using techniques like fracking,” John Staub, a petroleum exploration and production analyst who led the energy agency's research, told the Times.

How could this be in light of the all the optimistic projections?

“Our oil production estimates combined with a dearth of knowledge about geological differences among the oil fields led to erroneous predictions and estimates,” Staub said.

Not everyone has been in the dark about the Monterey Shale. Bob Brackett, an analyst for the global asset management firm Alliance Bernstein, wrote a report in July 2012 that was skeptical of the field’s potential. “We don't expect a ‘Bakken Boom’ to strike the San Joaquin Valley,” Brackett wrote. “We expect California production to grow only modestly.”

Brackett suggested that certain geological characteristics could make drilling difficult and the oil product thick and sticky.

Staub called the Monterey Shale formation “stagnant” compared to the Bakken Shale in North Dakota, but held out hope that some new, unknown technology could one day bring the boon the oil industry has been promoting.

That's good enough for Tupper Hull, spokesman for the Western States Petroleum Association. He told the Times, “We have a lot of confidence in the intelligence and skill of our engineers and geologists to find ways to adapt.” Perhaps less regulation would help.